TWI662352B - Color organic pigments and electrophoretic display media containing the same - Google Patents

Abstract

An electrophoretic display medium includes front and rear electrodes, and at least one of the front and rear electrodes is transparent; and an encapsulated dispersion fluid including a plurality of pigments disposed between the front and rear electrodes. The plurality of pigments includes first and second types of organic pigment particles. The first type of organic pigment particles have a first color and a first charge polarity. The second type of organic pigment particles have a second color different from the first color, and the second charge polarity is the same as the first charge polarity. At least one of the first and second types of organic pigment particles includes a silicon dioxide coating and a polymer stabilizer covalently bonded to the silicon dioxide coating.

Description

   Color organic pigment and electrophoretic display medium containing the same   

Cross-references in related applications

This application claims the priority and benefits of US Provisional Patent Application No. 62 / 448,683 filed on January 20, 2017, the contents of which are incorporated herein by reference in their entirety.

Field of invention

The invention relates to an organic pigment used in an electrophoretic display medium. More specifically, in one aspect, the present invention relates to an electrophoresis system including organic pigments of a plurality of different colors and having similar charge polarity.

When applied to a material or a display, the term "photoelectricity" is used herein in its conventional sense in imaging technology, and refers to a material having a first and a second display state, wherein the first and second The display states differ from each other in at least one optical property, wherein by applying an electric field to the material, the material changes from its first display state to its second display state. Although this optical property is typically a color recognizable by the human eye, it may be another optical property, such as light transmission, reflectance, luminosity, or in the case of a display intended for machine reading, false color, In terms of the change in reflectivity of electromagnetic wavelengths outside the visible range.

In the sense that the material has a solid outer surface, some optoelectronic materials are solid, however the material may and often has a space filled with liquid or gas inside. For convenience, this display using a solid photovoltaic material may be referred to as a "solid photovoltaic display" hereinafter. Therefore, the term "solid-state optoelectronic display" includes a rotating bichromal member display, an encapsulated electrophoretic display, a microcellular electrophoretic display, and an encapsulated liquid crystal display.

The terms "bistable" and "bistable" are used herein in their conventional sense in the art, and refer to the inclusion of a first and a second display, such as black and white, which differ in at least one optical property. The display of the status display element, and so that after any provided element has been driven to assume its first or second display state by an address pulse of a finite period, the state will persist after the address pulse has terminated For a period of time, it is at least several times, for example, at least four times, the minimum period of the address pulse required to change the state of the display element. Some particle-based electrophoretic displays are stable not only in their extreme black and white states, but also in three or more states, such as multicolor displays with three or more colors. For convenience, the term "bistable" as used herein may encompass display elements having two or more display states.

A type of electrophoretic display that has been intensive research and development for several years has a particle-based electrophoretic display, in which a plurality of charged particles move through a fluid under the influence of an electric field. When compared with liquid crystal displays, electrophoretic displays can have attributes of good brightness and contrast, wide viewing angles, state bistableness, and low power consumption. However, the long-term image quality issues of these displays have prevented their widespread use. For example, the particles that make up an electrophoretic display tend to settle, resulting in an inappropriate lifetime of these displays.

Many patents and applications belonging to or published by the Massachusetts Institute of Technology (MIT), E Ink Corporation, E Ink California, LLC and related companies describe a variety of applications in encapsulation and microcellular electrophoresis and other optoelectronic media. technology. The encapsulated electrophoretic medium contains a number of small capsules, each of which contains an internal phase, which consists of particles in a fluid medium that will move electrophoretically; and a capsule wall surrounding the internal phase. Typically, the capsules themselves are contained in a polymer binder to form a coherent layer disposed between two electrodes. In a microcellular electrophoretic display, the charged particles and fluid are not encapsulated in the microcapsules, but are instead retained in a plurality of cavities formed in a carrier medium, where the carrier medium is typically a polymer film. Techniques described in these patents and applications include: (a) electrophoretic particles, fluids, and fluid additives; see, for example, U.S. Patent Nos. 7,002,728 and 7,679,814; (b) capsules, adhesives, and encapsulation methods; see, for example, the United States Patent Nos. 6,922,276 and 7,411,719; (c) Cell structure, wall material, and method for forming cells; see, for example, US Patent Nos. 7,072,095 and 9,279,906; (d) methods for filling and sealing cells; see, for example, U.S. Patent Nos. 7,144,942 and 7,715,088; (e) films and sub-equipment including optoelectronic materials; see, for example, U.S. Patent Nos. 6,982,178 and 7,839,564; (f) backsheets, adhesive layers, and other auxiliary layers and methods used in displays ; See, for example, U.S. Patent Nos. 7,116,318 and 7,535,624; (g) color formation and color adjustment; see, for example, U.S. Patent Nos. 6,017,584; 6,545,797; 6,664,944; 6,788,452; 6,864,875; 6,914,714; 6,972,893; 7,038,656; 7,038,670; 7,046,228 ;; 7,075,502; 7,167,155; 7,385,751; 7,492,505; 7,667,684; 7,684,108; 7,791,789; 7,800,813; 7,821,702; 7,839,564; 7,910,175; 7,952,790; 7,956,841; 7,982,941; 8,040,594; 8,054,526; 8,098,418; 8,159,636; 8,213,076; 8,363,299; 8,422,116; 8,441,714; 8,441,716; 8,466,852; 8,503,063; 8,576,470; 8,576,475; 8,593,721; 8,605,354; 8,649,084; 8,670,174; 8,704,756; 8,717,664; 8,786,935; 8,797,634; 8,810,899; 8,830,559; 8,873,129; 8,902,153; 8,902,491; 8,917,439; 8,964,282; 9,013,783; 9,116,412; 9,146,439; 9,164,207; 9,170,467; 9,170,468; 9,199,441;; 9,341,916;; 9,360,733; 9,361,836; 9,383,623; 9,182,646; 9,195,111 9,268,191; 9,285,649; 9,293,511 and 9,423,666 ; And U.S. Patent Application Publication Nos. 2008/0043318; 2008/0048970; 2009/0225398; 2010/0156780; 2011/0043543; 2012/0326957; 2013/0242378; 2013/0278995; 2014/0055840; 2014/0078576; 2014 / 0340430; 2014/0340736; 2014/0362213; 2015/0103394; 2015/0118390; 2015/0124345; 2015/0198858; 2015/0234250; 2015/0268531; 2015/0301246; 2016/0011484; 2016/0026062; 2016/0048054 ; 2016/0116816; 2016/0116818; and 2016/0140909; (h) a method for driving a display; see, for example, U.S. Patent Nos. 7,012,600 and 7,453,445; (i) applications of displays; see, for example, U.S. Patent Nos. 7,312,784 and 8,009,348; and ( j) Non-electrophoretic displays, as described in U.S. Patent No. 6,241,921 and U.S. Patent Application Publication No. 2015/0277160; and encapsulation and cell technology applications other than displays; see, for example, U.S. Patent Application Publication Case Nos. 2015/0005720 and 2016/0012710.

Many of the aforementioned patents and applications recognize that the wall of the discrete microcapsules can be replaced by a continuous phase in an encapsulated electrophoretic medium, thus creating a so-called polymer dispersed electrophoretic display, where the electrophoretic medium contains a plurality The discrete electrophoretic fluid droplets and the continuous phase of the polymeric material, and the discrete electrophoretic fluid droplets in this polymer-dispersed electrophoretic display can be regarded as capsules or microcapsules, even if there is no discrete capsule film associated with each individual droplet, See, for example, the aforementioned US Pat. No. 6,866,760. In addition, for the purpose of this application, this polymer-dispersed electrophoretic medium is regarded as a subtype of the encapsulated electrophoretic medium.

An electrophoretic display normally includes an electrophoretic material layer and at least two other layers disposed on opposite sides of the electrophoretic material. One of the two layers is an electrode layer. In most of these displays, the two layers are electrode layers, and one or both of the electrode layers are patterned to define the pixels of the display. For example, one electrode layer can be patterned into an elongated column electrode and another layer can be patterned into an elongated row electrode at a right angle to the column electrode, and the pixels are defined by the intersection of the column and the row electrode. Optionally and more generally, one electrode layer has a single continuous electrode form and the other electrode layer is patterned into a pixel electrode matrix, each of which defines a pixel of the display. In another type of electrophoretic display, it is intended to use a detection head, a print head, or a similar movable electrode that is separate from the display, and only one of the layers adjacent to the electrophoretic layer contains an electrode on the opposite side of the electrophoretic layer The upper layer is typically a protective layer intended to prevent the movable electrode from damaging the electrophoretic layer.

Encapsulated electrophoretic displays typically do not encounter the agglomeration and sink failure modes of traditional electrophoretic devices and provide further advantages, such as the ability to print or coat the display on a wide variety of flexible and rigid substrates. (The use of the word "printing" is intended to include all forms of printing and coating, including, but not limited to, predictive supply coating methods such as patch die coating, slit or extrusion coating Cloth, sliding or step coating, curtain coating; roll coating methods such as knife over roll coating, forward and reverse roll coating; gravure coating; dip coating Cloth method; spray coating method; meniscus liquid surface coating method; spin coating method; brush coating method; air knife coating method; screen printing method; electrostatic printing method; thermal printing method; inkjet printing method; electrophoresis Deposition (see U.S. Patent No. 7,339,715); and other similar technologies). Therefore, the resulting display is flexible. Furthermore, because the display medium can be printed (using a variety of methods), the display itself can be made inexpensively.

However, the effective life of the encapsulated electrophoretic display is still completely lower than desired. It has been shown that this effective lifetime is limited by factors such as the tendency of the particles to cluster into clusters that prevent the particles from moving as needed to complete the display's switching between its optical states. The physical properties and surface characteristics of electrophoretic particles can be modified by adsorbing multiple materials on the surface of the particles, or by chemically bonding multiple materials to these surfaces. For example, in an electrophoretic display including an organic pigment, monomers having different chemical groups may be formed on the pigment by a dispersion polymerization method, and the coating may be reacted with a charge control agent to provide Colored particles with different charge intensities. However, it has been observed that as the number of colors increases, certain polymer-coated pigments of different colors can be difficult to separate from each other due to the structural similarity of the coated polymers. Another method is to use inorganic color pigments, but the color intensity and brightness of organic pigments are better than inorganic pigments. Because organic pigments are preferred, there is a need to improve color optoelectronic displays including electrophoretic media that include a plurality of colored organic particles.

According to one aspect of the present invention, an electrophoretic display medium includes front and back electrodes; and an encapsulated dispersion fluid including a plurality of pigments disposed between the front and back electrodes. At least one of the front and rear electrodes may be transparent. The plurality of pigments include first and second types of organic pigment particles. The first type of organic pigment particles may have a first color and a first charge polarity. The second type of organic pigment particles may have a second color different from the first color and a second charge polarity that is the same as the first charge polarity. At least one of the first and second types of organic pigment particles includes a silica coating and a polymer stabilizer bound to the silica coating.

These and other aspects of the invention will be apparent in view of the following description.

11‧‧‧ the first type of particles

12‧‧‧Second type granules

13‧‧‧ The third type of particles

14‧‧‧ The fourth type of particles

15‧‧‧Common electrode

16‧‧‧ electrode layer

16a‧‧‧pixel electrode

17‧‧‧ the first surface

18‧‧‧ second surface

The drawings are drawn by way of example only, and are not intended to be limiting.

The figure depicts an electrophoretic display device according to a specific example of the present invention.

In the following detailed description, many specific details are provided through the examples to provide a complete understanding of the relevant teachings. However, it should be clear to those skilled in the art that this teaching can be carried out without such details.

According to a specific example of the present invention, an electrophoretic display medium that can be incorporated into a photoelectric display is provided. The photovoltaic display may include front and rear electrodes, at least one of the front and rear electrodes being transparent; and an encapsulated dispersion fluid including a plurality of pigments disposed between the front and rear electrodes. The plurality of pigments may include first and second types of organic pigment particles. The first type of organic pigment particles may have a first color and a first charge polarity, and the second type of organic pigment particles may have a second color and a second charge polarity. The first color and the second color may also be different, and at the same time, the first and second charge polarities are the same.

The electrophoretic display medium may optionally further include a third type of organic pigment having a third color and a third charge polarity, and both the third color and the third charge polarity are related to the first and second colors and the first And the second charge has a different polarity. Each of the first, second, and third types of organic pigment particles may include, but is not limited to, CI pigments PR254, PR122, PR149, PG36, PG58, PG7, PB28, PB15: 1, PB15: 2, PB15: 3, PB15 : 4, PY83, PY138, PY150, PY151, PY154, PY155 or PY20, and other color index manuals, "New Pigment Application Technology" (CMC Publishing Co., Ltd, 1986) and "Printing Ink Technology" (CMC Publishing Co. , Ltd., 1984) as commonly used organic pigments. Specific examples include Clariant Hostaperm Red D3G 70-EDS, Hostaperm Pink E-EDS, PV fast red D3G, Hostaperm red D3G 70, Hostaperm Blue B2G-EDS, Hostaperm Yellow H4G-EDS, Novoperm Yellow HR-70-EDS, Hostaperm Green GNX, BASF Irgazine red L 3630, Cinquasia Red L 4100 HD and Irgazin Red L 3660 HD; Sun Chemical phthalocyanine blue, phthalocyanine green, diarylide yellow or benzidine AAOT yellow. In addition, the colors of the first, second, and third types of organic pigment particles may independently be, for example, red, green, blue, cyan, magenta, or yellow.

In addition to color, the particles may have other distinguishable optical characteristics, such as light transmission, reflectance, luminescence, or, in the case of a display intended for machine reading, pseudo-color, which is outside the visible range In terms of the change in reflectivity at electromagnetic wavelengths.

According to various embodiments of the present invention, at least one of the first and second types of organic pigment particles includes a silicon dioxide coating, and a polymer stabilizer may be bonded thereto. In a specific example, the polymer stabilizer may include a polymer including a silane coupling group, and the silane group is covalently bonded to the silicon dioxide coating. In another specific example, the polymer stabilizer may be ionic bonded to a silane coupling agent having a silane group, and the silane group may be covalently bonded to the silicon dioxide coating.

With particular reference now to the drawings, the electrophoretic fluid may include four types of particles dispersed in an encapsulated dispersion fluid, such as a dielectric solvent or a solvent mixture. For ease of explanation, the four types of pigment particles may be referred to as particles of the first type (11), the second type (12), the third type (13), and the fourth type (14), as shown in the drawings. Although only four types of pigment particles are used, a display device using the electrophoretic fluid can display at least five different color states, which results in a full-color display. The dispersion fluid may be encapsulated according to any method known to those skilled in the art, for example, microcapsules, cells, or polymer matrices; and encapsulated into any size or shape, such as, for example, spherical, and may have a diameter in the millimeter In the range or micrometer range, but preferably about ten to about several hundred micrometers.

Various coating methods can be used to provide organic pigment particles containing a silicon dioxide coating. For example, the coating method described in US Patent 3,639,133 provides an example of a coating method, the contents of which are incorporated herein by reference in their entirety. Before coating the organic pigment particles, the particles can be prepared by first using various known methods such as ultrasonic, ball milling, jet milling, etc. to de-agglomerate and homogenize the aqueous slurry of the organic pigment particles. A dispersant may be added to the aqueous slurry to maintain deagglomeration of the pigment particles. In one method, the organic pigment particles are dispersed in a solution of ethanol and tetraethyl orthosilicate and reacted at room temperature under alkaline conditions for 20 hours to form a generally uniform dioxide on the particles. Silicon coating. The coating is preferably 0.5 to 10 nanometers thick, more preferably 1 to 5 nanometers.

After the deposition of the silicon dioxide coating is completed, the pH of the reaction mixture may be lowered to less than about 4 and preferably to about 3 before the silica-coated particles are separated from the reaction mixture. This pH reduction is conveniently achieved using sulfuric acid, however other acids such as nitric acid, hydrochloric acid and perchloric acid can be used. The particles are conveniently separated from the reaction mixture by centrifugation. After this separation, the particles need not be dried. Moreover, the silica-coated particles can be easily redispersed in a medium, typically an alcohol-containing aqueous medium, to be used in the next step of the method to form a polymer stabilizer on the particles. This enables the pigment particles coated with silicon dioxide to be maintained in an unagglomerated and uncombined form when undergoing the attachment process of polymerizable or polymeric starting groups, thus allowing the pigment particles to be completely covered by this group, And to prevent the formation of large aggregates of pigment particles in microcapsules typically formed from the silica-coated pigment. When the silica-coated pigment is intended to be used in small microcapsules (less than about 100 microns in diameter), it is particularly important to prevent the formation of such agglomerations; and the small microcapsules are desirable because they reduce the electrophoretic media Operating voltage and / or switching time.

According to a first embodiment of the present invention, the polymer stabilizer may be derived from one or more monomers or macromonomers using a variety of polymerization techniques known to those skilled in the art. For example, the polymer stabilizer on the silica-coated organic pigment particles can be obtained by random graft polymerization (RGP), ion random graft polymerization (IRGP), and atom transfer radical polymerization (ATRP). , As described in US Patent No. 6,822,782, the contents of which are incorporated herein by reference in their entirety. As used throughout the scope of patent specifications and patent applications, "macromonomer" means herein a macromolecule with a terminal group capable of acting as a monomer.

Monomers suitable for forming the polymer stabilizer may include, but are not limited to, styrene, α-methylstyrene, methyl acrylate, methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, and triacrylate Butyl, tert-butyl methacrylate, vinylpyridine, N-vinylpyrrolidone, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, dimethylaminoethyl methacrylate , Lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate , N-octadecyl acrylate, n-octadecyl methacrylate, 2-perfluorobutyl ethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3 methacrylate, 3-tetrafluoropropyl ester, acrylic acid 1,1,1,3,3,3-hexafluoroisopropyl ester, methacrylic acid 1,1,1,3,3,3-hexafluoroisopropyl ester, acrylic acid 2, 2,3,3,3-pentafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate and methacrylic acid 2,2,3,3,4,4,4-heptafluorobutyl ester or its analog. The macromonomer may include a terminal functional group selected from the group consisting of an acrylate group, a vinyl group, or a combination thereof.

In the method of the present invention, any pair of groups having one group capable of covalently bonding to the silica coating and another group capable of covalently or ionicly bonding to the monomer or macromonomer can be used. A functional group compound that attaches the polymerizable monomer or macromonomer to the surface of the silica-coated pigment particles. In one embodiment, the compound may be a silane having at least one polymerizable group, such as the polymerizable monomers listed above (e.g., 3- (trimethoxysilyl) propyl methacrylate).

The polymer stabilizer may be formed from a reactive and polymerizable monomer or macromonomer, where the monomer or macromonomer will adsorb, become incorporated or chemically bond to use to bridge the silica coating with Bifunctional compounds of polymer stabilizers. The polymer stabilizer determines the particle size and colloidal stability of the system, and preferably a long polymer chain with composite pigment particles that can be stabilized in a hydrocarbon solvent.

In describing the reagents used to provide the desired polymerizable functional group or starting functional group, we do not exclude the possibility that the polymer stabilizer may have a "difunctional group". For example, it is known that a polymerization initiator such as 4,4'-azobis (4-cyanovaleric acid) has more than one ionic position, and this initiator can be used in the present method. Similarly, as mentioned previously, the difunctional compound may have the form of a macromonomer, which includes a repeating unit having the ability to bond to the surface of the particle and having a desired polymerizable functional group or starting function Other repeating units based on this group, and this macromonomer bifunctional compound can form polymer stabilizers that would normally include multiple of these two types of repeating units.

A preferred type of functional group for bonding to a silica-coated pigment is a silane coupling group, particularly a trialkoxysilane coupling group. A particularly preferred reagent for attaching polymerizable groups to titanium dioxide and similar pigments is the aforementioned 3- (trimethoxysilyl) propyl methacrylate, which is available from the Dow Chemical Company, Wilmington, Del. Commercially available under the trade name Z6030. Corresponding acrylates can also be used.

One type of macromonomer used as a polymer stabilizer may be an acrylate-terminated polysiloxane such as, for example, Gelest, MCR-M11, MCR-M17, or MCR-M22. Another type of macromonomer suitable for this method is the PE-PEO macromonomer as shown below: R _m O-[-CH ₂ CH ₂ O--] _n --CH ₂ -phenyl-CH = CH ₂ ; or R _m O-[-CH ₂ CH ₂ O--] _n --C (= O)-C (CH ₃ ) = CH ₂ .

The substituent R may be a polyethylene chain, n is 1-60 and m is 1-500. The synthesis of these compounds can be found in Dongri Chao et al., Polymer Journal, Vol. 23, No. 9, 1045 (1991) and Koichi Ito et al., Macromolecules, 1991, 24, 2348. Further suitable macromonomer types are PE macromonomers as shown in the following: CH ₃ -[-CH _2- ] _n --CH ₂ O--C (= O)-C (CH ₃ ) = CH ₂ .

In this case, n is 30-100. The synthesis of this macromonomer type can be found in Seigou Kawaguchi et al., Designed Monomers and Polymers, 2000, 3, 263.

When the difunctional compound is selected so as to provide a polymerizable functional group or a starting functional group on the particles, it should be noted that the relative positions of the two groups in the reagent. As should be understood by those familiar with polymer manufacturing, the reaction rate at which the polymerizable functional group or the starting group is bonded to the particle can greatly depend on whether the group remains fixed close to the surface of the particle, or whether the group is in contact with the surface of the particle. The surface is spaced apart (on an atomic scale) and can therefore vary by extending into the reaction medium surrounding the particle, and this system is more suitable for the environment in which the group performs a chemical reaction. In general, it is best to have at least three atoms in the direct chain between two functional groups. For example, the aforementioned 3- (trimethoxysilyl) propyl methacrylate is unsaturated in the silyl group with ethylenic unsaturated A chain of four carbons and one oxygen atom is provided between the groups, and the 4-vinylaniline mentioned above separates the amine group by a full-width benzene ring (this is equivalent to the length of about three carbon chains). In the actual reaction form, the diazo group) and vinyl group.

In any of the above methods, the amount of reagents (e.g., organic core pigment particles, silica shell materials, and materials used to form the polymer stabilizer) can be adjusted and controlled to produce a composite pigment The desired organic content is achieved in the particles. Furthermore, the method of the present invention may include more than one stage and / or more than one polymerization pattern.

As mentioned above, the particles made according to various embodiments of the present invention are dispersed in an encapsulation fluid. It is desirable that the polymer stabilizer is highly compatible with the encapsulated fluid. In practice, the suspension fluid in the electrophoretic medium is normally based on hydrocarbons, but the fluid may include a certain proportion of halogenated carbon, which is used to increase the density of the fluid and thus reduce the difference between the density of the fluid and the density of the particles. In addition, it is important that the polymer stabilizer formed in this method is highly compatible with the encapsulated fluid, so the polymer stabilizer itself contains a major proportion of hydrocarbon chains; Except for the purpose of the charge, a large number of strong ionic groups are not desired, because they will make the polymer stabilizer less soluble in the hydrocarbon suspension fluid, and thus adversely affect the stability of the particle dispersion. Likewise, as already discussed, polymer stabilizers having a branched or "comb-type" structure are advantageous, at least when the medium to be used by the particles contains an aliphatic hydrocarbon suspension fluid (as is usually the case), where the comb-type The structure has a main chain and a plurality of side chains extending from the main chain. Each of these side chains should have at least about four and preferably at least about six carbon atoms. In essence, longer side chains can be excellent, for example, some preferred polymer stabilizers can have lauryl (C ₁₂ ) side chains. The side chain may itself be branched, for example, each side chain may be a branched alkyl group, such as 2-ethylhexyl. Salt letter (however, the invention is by no means limited by this letter), because the hydrocarbon chain has a high affinity for a hydrocarbon-based suspension fluid, and the branches of the polymer stabilizer are in a brush or tree structure with each other via a large volume of liquid Spread apart, thus increasing the affinity of the particles for the suspended fluid and the stability of the particle dispersion.

There are two basic methods to form this comb-type polymer. The first method uses monomers that inherently provide the required side chains. Typically, this monomer has a single polymerizable group at one end of a long chain (at least four and preferably at least six carbon atoms). Monomers of this type that have been found to provide good results in this process include hexyl acrylate, 2-ethylhexyl acrylate, and lauryl methacrylate. Isobutyl methacrylate and 2,2,3,4,4,4-hexafluorobutyl acrylate have also been used successfully. In some cases, it may be desirable to limit the number of side chains formed in this method, and this may be achieved by using a mixture of monomers (e.g., a mixture of lauryl methacrylate and methyl methacrylate) to form only This is achieved by some repeating units bearing random copolymers of this long side chain. In the second method, symbolized by the RGP-ATRP method, a mixture of monomers is used for the first polymerization reaction. At least one of these monomers carries a starting group, so a first group including this starting group is produced. polymer. Then, the product of the first polymerization reaction is typically subjected to a second polymerization under conditions different from the first polymerization, so that the starting group in the polymer causes additional monomers to polymerize to the original polymer , Thus forming the desired side chain. When using the bifunctional reagents discussed above, we do not rule out the possibility that some chemical modification of the starting group can be achieved between the two polymerization reactions. In this method, the side chain itself need not be largely branched and can be formed from small monomers such as methyl methacrylate.

Ethylene or similar attachment to the particles can be achieved at elevated reaction temperatures, preferably 60 to 70 ° C, using conventional free radical initiators such as azobis (isobutyronitrile) (AIBN) Radical polymerization of radical polymerizable groups; ATRP polymerization can also be achieved using conventional metal complexes, such as in Wang, JS et al. Macromolecules 1995, 23, 7901; and J. Am. Chem. Soc. 1995, 117 , 5614; and described in Beers, K. et al., Macromolecules 1999, 32, 5772-5776. See also U.S. Pat. The entire disclosure of these documents and patents are incorporated herein by reference. The preferred catalyst currently used for ATRP is cuprous chloride in the presence of bispyridyl (Bpy).

The RGP method of the present invention is to allow the particles bearing a polymerizable group to react with a monomer in the presence of a starter. When the monomer in the reaction mixture is polymerized, it will inevitably cause the formation of some missed bonds. A "free state" polymer attached to the particles. The particles can be washed repeatedly by using the unattached polymer-soluble solvent (typically a hydrocarbon); or (at least in the case of metal oxides or other dense particles) by using the reaction mixture (containing or (Without pre-added solvents or diluents), centrifuge the treated particles, re-disperse the particles in fresh solvent, and repeat these steps until the proportion of unattached polymers has been reduced to an acceptable level. The unattached polymer is removed. (The decreasing proportion of unattached polymer can follow the thermogravimetric analysis of the polymer sample). Empirically, the presence of a small proportion of unattached polymers in the order of 1 weight percent does not show any serious deleterious effects on the electrophoretic properties of the treated particles; more precisely, in some cases Depending on the chemical nature of the unattached polymer and suspension fluid, it is not necessary to separate the unattached polymer from the particles to which the polymer stabilizer is attached before the particles are used in an electrophoretic display.

As indicated, it has been found that the polymer stabilizers formed on the electrophoretic particles should have an optimal amount range, and the formation of excess polymer on the particles can reduce their electrophoretic characteristics. The optimal range will vary with a number of factors, including the density and size of the particles to be coated, the nature of the suspension medium that the particles are intended to use, and the nature of the polymer formed on the particles; and for any particular particle, polymer For substances and suspension media, the optimal range is best determined empirically. However, as a general guide, it should be noted that the denser the particles, the lower the optimal ratio of the polymer of the particles by weight; and the finer the particles, the higher the optimal ratio of the polymer. . In general, the particles should be coated with at least about 2 and desirably at least about 4 weight percent of the particles in weight percent of the particles. In most cases, the most desirable proportion of the polymer will be about 4 to about 15 weight percent of the particles, and typically about 6 to about 15 weight percent, and most desirably about 8 to about 12 weight percent .

In order to incorporate a functional group capable of generating a charge to the pigment particles, a co-monomer may be added to the polymerization reaction medium. The comonomer may directly charge the composite pigment particles or have an interaction with a charge control agent in the display fluid to bring a desired charge polarity and charge density to the composite pigment particles. Suitable comonomers can include vinylbenzylaminoethylamino-propyl-trimethoxysilane, methacryloxypropyltrimethoxysilane, acrylic acid, methacrylic acid, vinyl phosphoric acid, 2 -Propenylamino-2-methylpropanesulfonic acid, 2- (dimethylamino) ethyl methacrylate, N- [3- (dimethylamino) propyl] methacrylamidine And its analogs. Suitable comonomers may also include fluorinated acrylates or methacrylates, such as 2-perfluorobutyl ethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2 methacrylate , 3,3-tetrafluoropropyl ester, acrylic acid 1,1,1,3,3,3-hexafluoroisopropyl ester, methacrylic acid 1,1,1,3,3,3-hexafluoroisopropyl ester, 2,2,3,3,3-pentafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate or 2,2,3,3,4,4,4-heptafluorobutyl methacrylate. Alternatively, a charged or chargeable group may be incorporated into the polymer via a bifunctional stabilizer that is used to provide a polymerizable functional group or a starting functional group to the pigment.

During the polymerization, functional groups such as acidic or basic groups can be provided in an "hindered" form, which can then be deblocked after the polymer is formed. For example, because ATRP cannot be initiated in the presence of an acid, if it is desired to provide acidic groups in the polymer, esters such as tertiary butyl acrylate or isomethacrylate Esters, and in the final polymer, residues of these monomers are hydrolyzed to provide acrylic or methacrylic acid residues.

When it is desired to generate charged or chargeable groups on the pigment particles and a polymer stabilizer is also attached to the particles, it is very convenient to treat the particles with a mixture of two agents (in the dioxide After silicon coating), where one of the reagents carries the charged or chargeable group (or will be finally processed to produce the desired charged or chargeable group), and the reagent The other carries the polymerizable or polymerizable starting group. It is desirable that the functional groups of the two reagents that react with the particle surface are the same or substantially the same, so that if there is a small change in the reaction conditions, the relative rate of reaction between the reagents and the particles will change in a similar manner, and The ratio between the number of charged or chargeable groups and the number of the polymerizable group or the polymerization initiating group will remain substantially constant. It will be appreciated that this ratio can be changed and controlled by varying the relative molar amounts of the two (or more) reagents used in the mixture. Examples of reagents that provide a chargeable position without a polymerizable group or a polymerization initiating group include 3- (trimethoxysilyl) propylamine, N- [3- (trimethoxysilyl) propyl] di Ethyltriamine, N- [3- (trimethoxysilyl) propyl] ethylene and 1- [3- (trimethoxysilyl) propyl] urea; all of these silane reagents are available from United Chemical Technologies, Inc., Bristol, Pa., 19007. As already mentioned, an example of a reagent that provides polymerizable groups but has no charged or chargeable groups is 3- (trimethoxysilyl) propyl methacrylate.

In addition to the colored organic pigment particles, different specific examples of the electrophoretic display medium according to the present invention may further include at least one type of inorganic pigment particles. The inorganic pigment particles may also be coated with silicon dioxide and a polymer stabilizer, as described, for example, in US Patent No. 6,822,782. The white particles may be formed from an inorganic pigment such as TiO ₂ , ZrO ₂ , ZnO, Al ₂ O ₃ , Sb ₂ O ₃ , BaSO ₄ , PbSO ₄ or the like. The black particles may be formed from CI pigment black 26 or 28 or the like (for example, manganese ferrite black spinel or copper chromite black spinel), carbon black, zinc sulfide, and combinations thereof.

Four types of particles are usually divided into two groups, a high-charge group and a low-charge group. Of the two groups of oppositely charged particles, one group carries a stronger charge than the other. Therefore, the four types of pigment particles can also be referred to as high-positive particles, high-negative particles, low-positive particles, and low-negative particles.

As for the embodiment, the red particles (R) and the white particles (W) may be the first group of oppositely charged particles, and in this group, the red particles are highly positive particles and the white particles are highly negative particles. The blue particles (B) and the green particles (G) may be a second group of oppositely charged particles, and in this group, the blue particles are low-positive particles and the green particles are low-negative particles.

In another embodiment, the red particles can be high-positive particles; the white particles can be high-negative particles; the blue particles can be low-positive particles and the yellow particles can be low-negative particles. It is to be understood that the scope of the present invention broadly includes particles of any color as long as the four types of particles have a visually discernible color.

As also shown in the drawings, the display layer using the display fluid of the present invention has two surfaces, a first surface (17) on the viewing side and a second surface on the opposite side of the first surface (17) (18). The display flow system is sandwiched between the two surfaces. There is a common electrode (15) on the first surface (17) side, which is a transparent electrode layer (for example, ITO), which is distributed on the entire top of the display layer. There is an electrode layer (16) on the second surface (18) side, which contains a plurality of pixel electrodes (16a).

This pixel electrode is described in U.S. Patent No. 7,046,228, the contents of which are incorporated herein by reference in their entirety. It should be noted that although the active matrix drive and thin film transistor (TFT) backplane is mentioned for the pixel electrode layer, the scope of the present invention includes other types of electrode addressing as long as the electrode provides the desired function.

In the drawing, each space between two virtual vertical lines is indicated as a pixel. As shown, each pixel has a corresponding pixel electrode. An electric field is generated for a pixel by a potential difference between a voltage applied to the common electrode and a voltage applied to a corresponding pixel electrode.

The percentage of the four types of particles in the fluid can vary. For example, one type of particles may occupy 0.1% to 50%, preferably 0.5% to 15%, based on the volume of the electrophoretic fluid.

It should also be noted that the four types of particles may have different particle sizes. Useful sizes can range from 1 nanometer to up to about 100 microns. For example, smaller particles may have a size ranging from about 50 nanometers to about 800 nanometers. The larger particles may have a size that is about 2 to about 50 times, and more preferably about 2 to about 10 times the size of the smaller particles.

The density of the electrophoretic particles may be substantially commensurate with the suspension (ie, electrophoretic) fluid. As defined herein, if the difference in their respective densities is between about zero and about two grams per milliliter ("g / ml"), the density of the suspension fluid is "substantially commensurate with the density of the particles" ". This difference is preferably between about zero and about 0.5 g / ml.

The solvent in which the four types of particles are dispersed is transparent and colorless. For high particle mobility, it is preferred that it has low viscosity and a dielectric constant in the range of about 2 to about 30, preferably about 2 to about 15. Examples of suitable dielectric solvents include hydrocarbons such as isopar, decalin, 5-ethylidene-2-nor Olefins, fatty oils, paraffin oils, silicone fluids; aromatic hydrocarbons such as toluene, xylene, phenylxylylethane, dodecylbenzene, or alkylnaphthalenes; halogenated solvents such as perfluoronaphthalene, perfluoro Toluene, perfluoroxylene, dichlorotrifluorotoluene, 3,4,5-trichlorotrifluorotoluene, chloropentafluoro-benzene, dichlorononane or pentachlorobenzene; and perfluorinated solvents such as from 3M Company, St. Paul MN's FC-43, FC-70 or FC-5060; low molecular weight halogen-containing polymers such as poly (perfluoropropylene oxide) from TCI America, Portland, Oregon; poly (chlorotrifluoro- Ethylene), such as Halocarbon Oils from Halocarbon Product Corp., River Edge, NJ; perfluoropolyalkyl ethers, such as Galden from Ausimont or Krytox Oils and Greases K-Fluid series from DuPont, Delaware; from Dow-Corning Polydimethylsiloxane based polysiloxane (DC-200).

In one specific example, the charge carried by the "low-charge" particles may be less than about 50%, or from about 5% to about 30%, of the charge carried by the "high-charge" particles. In another specific example, the "low-charge" particles may be less than about 75%, or about 15% to about 55%, of the charge carried by the "high-charge" particles. In a further specific example, a comparison of the degree of charge as indicated is applied to two types of particles having the same charge polarity.

This charge intensity can be measured in terms of zeta potential. In a specific example, the zeta-potential is determined by the Colloidal Dynamics AcoustoSizer IIM and CSPU-100 signal processing unit, ESA EN # Attn flow through cell (K: 127). Enter the instrument constants before the test, such as the density of the solvent used in the sample, the dielectric constant of the solvent, the speed of sound in the solvent, and the viscosity of the solvent, all of which are at the test temperature (25 ° C). A pigment sample is dispersed in a solvent, which is typically a hydrocarbon fluid having less than 12 carbon atoms, and diluted to between 5-10% by weight. The sample also included a charge control agent (Solsperse 17000®, available from Lubrizol Corporation, Berkshire Hathaway Company; "Solsperse" is a registered trademark), wherein the weight ratio of the charge control agent to particles was 1:10. The quality of the diluted sample is determined, and then the sample is loaded into a flow cell to determine the zeta potential.

The number of "high positive" particles and "high negative" particles may be the same or different. Likewise, the number of "low positive" particles and "low negative" particles may be the same or different.

It should also be noted that in the same fluid, the two groups of high and low charge particles may have different degrees of charge difference. For example, in one group, the low-positive-charge particles may have a charge strength that is 30% of the charge-intensity of the high-positive-charge particles, and in another group, the low-negative-charge particles may have a charge strength that is the high-negative 50% of the charge strength of the charged particles.

A charge control agent with or without a charge group can be used in the polymer coating to provide good electrophoretic mobility for the electrophoretic particles. Stabilizers can be used to prevent agglomeration of electrophoretic particles and to prevent irreversible deposition of electrophoretic particles on the capsule wall. Either component can be constructed from materials (low molecular weight, oligomeric, or polymer) that span a wide range of molecular weights, and can be a single pure compound or mixture. The charge control agent used to modify and / or stabilize the surface charge of the particles is applied as is generally known in the art of liquid toners, electrophoretic displays, non-aqueous coating dispersions, and motor oil additives. In all of these techniques, charged species can be added to non-aqueous media to increase electrophoretic mobility or increase electrostatic stability. As such, the material can improve space stability. Different charged theories have been assumed, including selective ion adsorption, proton transfer, and contact electrification.

A selective charge control agent or charge director can be used. These constituents typically consist of a low molecular weight surfactant, a polymer agent, or a blend of one or more components, and are provided to modify or otherwise modify the sign and / or size of the charge on the electrophoretic particles. Additional pigment properties that may be relevant are particle size distribution, chemical composition, and light resistance.

Charge auxiliary agents can also be added. These materials increase the efficiency of charge control agents or charge directors. The charge adjuvant may be a polyhydroxy compound or an amino alcohol compound, and is preferably dissolved in the suspension fluid in an amount of at least 2% by weight. Examples of polyhydroxy compounds including at least two hydroxyl groups include, but are not limited to, ethylene glycol, 2,4,7,9-tetramethyldecyne-4,7-diol, poly (propylene glycol), pentaethylene glycol, Tripropylene glycol, triethylene glycol, glycerol, neopentyl tetraol, glycerol (12-hydroxystearate), glycidyl monohydroxystearate and ethylene glycol monostearate. Examples of amino alcohol compounds that include at least one alcohol functionality and one amine functionality in the same molecule include, but are not limited to, triisopropanolamine, triethanolamine, ethanolamine, 3-amino-1-propanol, ortho- Aminophenol, 5-amino-1-pentanol and (2-hydroxyethyl) ethylenediamine. The charge adjuvant is preferably present in the suspension fluid in an amount of from about 1 to about 100 milligrams ("mg / g") per gram of particle mass, and more preferably from about 50 to about 200 mg / g.

In general, salty charges cause acid-base reactions between the parts present in the continuous phase and the surface of the particles. Thus useful materials are those that can participate in this reaction or any other charged reaction as known in the art.

Different non-limiting types of useful charge control agents include organic sulfates or sulfonates, metal soaps, block or comb-type copolymers, organic amidines, organic zwitterions, and organic phosphates and phosphonates. Useful organic sulfates and sulfonates include, but are not limited to, sodium bis (2-ethylhexyl) sulfosuccinate, calcium dodecylbenzenesulfonate, calcium petroleum sulfonate, neutral or basic dinonylnaphthalene Barium sulfonate, neutral or basic calcium dinonylnaphthalenesulfonate, sodium salt of dodecylbenzenesulfonate, and lauryl ammonium sulfate. Useful metal soaps include, but are not limited to, alkaline or neutral barium petronate, calcium petronate; Co--, Ca--, Cu--, Mn-- , Ni--, Zn--, and Fe-- salts; Ba--, Al--, Zn--, Cu--, Pb--, and Fe-- salts of stearic acid; divalent and trivalent metal carboxylates Acid salts such as aluminum tristearate, aluminum octoate, lithium heptanoate, iron stearate, iron distearate, barium stearate, chromium stearate, magnesium octoate, calcium stearate, iron naphthenate , Zinc naphthenate; Mn-- and Zn-- heptanoic acid; and Ba--, Al--, Co--, Mn-- and Zn-- octoate. Useful block or comb type copolymers include, but are not limited to, AB diblock copolymers: (A) 2- (N, N-dimethylamino) methacrylate quaternized with methyl p-toluenesulfonate ) Polymers of ethyl esters, and (B) poly (2-ethylhexyl methacrylate); and comb-type graft copolymers having an oil-soluble poly (12-hydroxystearic acid) tail and having It has a molecular weight of about 1800 and is suspended on an oil-soluble anchor group of poly (methyl methacrylate-methacrylic acid). Useful organic amidines include, but are not limited to, polyisobutylene succinimines such as OLOA 371 or 1200 (available from Chevron Oronite Company LLC, Houston, Tex.), Or Solsperse 19000 and Solsperse 17000 (available from Avecia Ltd., Blackley, Manchester, United Kingdom; "Solsperse" is a registered trademark), and N-vinylpyrrolidone polymer. Useful organic zwitterions include, but are not limited to, lecithin. Useful organic phosphates and phosphonates include, but are not limited to, sodium salts of phosphorylated mono- and diglycerides with saturated and unsaturated acid substituents.

Particle dispersion stabilizers can be added to prevent the particles from agglomerating or attaching to the capsule wall. For typical high resistivity liquids used as suspension fluids in electrophoretic displays, non-aqueous surfactants can be used. These include, but are not limited to, glycol ethers, acetylene glycols, alkanolamines, sorbitol derivatives, alkylamines, quaternary amines, imidazolines, dialkyl oxides, and sulfonated succinates.

If a bistable electrophoretic medium is desired, it may be desirable to include a polymer having a number average molecular weight in excess of about 20,000 in the suspension fluid, which polymer is not substantially adsorbed on the electrophoretic particles; poly (isobutylene) is used for this purpose Preferred polymers. See U.S. Patent No. 7,170,670, the entire disclosure of which is incorporated herein by reference.

[Example]

The following examples are provided as illustrative specific examples of the invention and are not intended to limit the scope of the invention.

Sample 1

30 grams of organic copper phthalocyanine blue pigment was dispersed in a solvent mixture of 100 ml of ethanol and 5 ml of water. Then, 1.5 g of ammonia was added to raise the pH. 3 grams of triethoxysilane (TEOS) was added and the mixture was stirred at room temperature for 20 hours. After coating, the particles were purified by washing-centrifugation-redispersing three times in ethanol.

Then, the silica-coated organic pigment particles were mixed with 30 g of methacryloxypropyltrimethoxysilane in 150 g of methyl ethyl ketone (MEK) solvent, and the temperature was 60-65 ° C. Underflow reflux to functionalize the silica-coated organic pigment particles. The particles so functionalized were then purified by washing-centrifuging-redispersing in isopropanol (IPA) twice.

Polymer growth on such a functionalized silica-coated pigment is carried out by free radical polymerization in toluene. 15 grams of the silylated pigment was added to 50 grams of toluene and sonicated in a three-necked flask for 1 hour. 30 grams of 2-ethylhexyl acrylate monomer was added to the flask and N2 was charged into the flask for 20 minutes to remove oxygen, and then the flask was heated to 65 ° C. 0.2 grams of AIBN in toluene solution was added to the flask. After 20 hours of reaction, the particles were purified by washing-centrifugation-redispersion in toluene three times.

An electrophoretic ink medium for photoelectric performance testing was prepared, which included 24% of coated titanium oxide particles in an isoparaffin solvent, 16% by weight of blue particles from the example of Sample 1, and 5% by weight of coating. Cloth polymer red particles, 5% by weight coated polymer yellow particles, 0.4% Solsperse® 17000 and other charge adjuvants.

Comparative sample 1

The procedure used to manufacture Sample 1 was repeated, except that the copper phthalocyanine blue pigment was replaced with cobalt aluminate blue spinel particles. As such, the encapsulation fluid includes more than 15% by weight of inorganic blue pigment particles.

Comparative sample 2

The procedure used to make Sample 1 was repeated, except that the organic copper phthalocyanine blue pigment was not coated with silica before forming the polymer stabilizer.

Test Methods

The electrophoretic medium is sealed between two transparent ITO-PET electrodes via a micro-cell packing sealing technique described in US Patent No. 6,859,302. With the waveform generator, the same driver is used to drive the test samples. Use an X-rite iOne spectrophotometer to measure L * a * b * optical performance at D65 lighting settings.

Results from testing electrophoretic media including pigment particles according to Sample 1, Comparative Sample 1 and Comparative Sample 2 are provided in Tables 1, 2 and 3 below.

Comparing the results of three different electrophoretic media, the colored particles of Sample 1 provided unexpectedly improved results of the photoelectric performance. When compared to the particles of Comparative Sample 2 which elucidated the decline of the red state, each of the optical states of sample 1, blue, red, and yellow, provided a more improved separation value. As expected, the blue state provided by the organic particles of Sample 1 provided superior photoelectric performance than the inorganic particles of Comparative Sample 1. Therefore, by providing organic pigment particles with a hybrid silica and polymer stabilizer coating, improved photovoltaic performance is achieved.

Although a preferred specific example of the present invention has been shown and described herein, it will be appreciated that this specific example is provided by way of example only. Many changes, changes, and substitutions will occur to those skilled in the art without departing from the spirit of the invention. It is therefore intended that the scope of the appended patent application cover all such variations as fall within the spirit and scope of the invention.

Claims (20)

An electrophoretic display includes: a front and rear electrode, at least one of the front and rear electrodes being transparent; and an encapsulated dispersion fluid including a plurality of pigments disposed between the front and rear electrodes, the plurality of The pigment includes first and second types of organic pigment particles, the first type of organic pigment particles having a first color and a first charge polarity; the second type of organic pigment particles having a second color and a second charge polarity; the The first color and the second color are different, the first and second charge polarities are the same, and at least one of the first and second types of organic pigment particles includes a silicon dioxide coating and has a covalent bond to A silane coupling group of a silane group of the silicon dioxide coating, and a polymer stabilizer bound to the silane coupling group. The electrophoretic display of claim 1, wherein the first and second types of organic pigments comprise an organic core each independently selected from the group consisting of: PB15: 1, PB15: 2, PB15: 3, PB15 : 4, PR254, PR122, PR149, PG36, PG58, PG7, PY138, PY150, PY151, PY154 and PY20. The electrophoretic display according to claim 2, wherein the first and second types of organic pigments are independently colored red, green, blue, cyan, magenta, or yellow. The electrophoretic display according to claim 1, wherein the plurality of pigments further comprise at least one type of inorganic pigment particles. The electrophoretic display according to claim 4, wherein the inorganic pigment particles are selected from the group consisting of metal oxide, manganese ferrite black, copper chromite black spinel, carbon black, Zinc sulfide and combinations thereof. The electrophoretic display of claim 1, wherein the plurality of pigments further includes a third type of organic pigment, which has a third color and a third charge polarity, the third color is different from the first and second colors, and the The third charge polarity is different from the first and second charge polarities. The electrophoretic display medium of claim 6, wherein the first, second and third types of organic pigments are each independently selected from the group consisting of: PB15: 1, PB15: 2, PB15: 3, PB15: 4. PR254, PR122, PR149, PG36, PG58, PG7, PY138, PY150, PY151, PY154 and PY20. The electrophoretic display according to claim 7, wherein the first and second types of organic pigments are independently colored red, green, blue, cyan, magenta, or yellow. The electrophoretic display of claim 6, wherein the plurality of pigments further comprise at least one type of inorganic pigment particles. The electrophoretic display of claim 1, wherein the polymer stabilizer is covalently bonded to the silane coupling group. The electrophoretic display of claim 10, wherein the polymer stabilizer is derived from a monomer or a macromonomer. The electrophoretic display according to claim 11, wherein the single system is selected from the group consisting of styrene, α-methylstyrene, methyl acrylate, methyl methacrylate, n-butyl acrylate, methyl N-butyl acrylate, tertiary butyl acrylate, tertiary butyl methacrylate, vinyl pyridine, N-vinyl pyrrolidone, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid Dimethylaminoethyl, lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate , N-octyl methacrylate, n-octadecyl acrylate, n-octadecyl methacrylate, 2-perfluorobutyl ethyl acrylate, 2,2,2-trifluoroethyl methacrylate, methyl 2,2,3,3-tetrafluoropropyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 1,1,1,3,3,3-hexafluoro methacrylate Isopropyl ester, 2,2,3,3,3-pentafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,4,4,4-hexamethacrylate Fluorobutyl and 2,2,3,3,4,4,4-Heptafluorobutyl methacrylate. The electrophoretic display according to claim 11, wherein the macromonomer includes a terminal functional group selected from the group consisting of an acrylate group, a vinyl group or a combination thereof. The electrophoretic display according to claim 1, wherein the polymer stabilizer is ionic bonded to the silane coupling group. The electrophoretic display of claim 14, wherein the polymer stabilizer is derived from a monomer or macromonomer including a radical polymerizable group. The electrophoretic display of claim 15, wherein the single system is selected from the group consisting of styrene, α-methylstyrene, methyl acrylate, methyl methacrylate, n-butyl acrylate, methyl N-butyl acrylate, tertiary butyl acrylate, tertiary butyl methacrylate, vinyl pyridine, N-vinyl pyrrolidone, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid Dimethylaminoethyl, lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate , N-octyl methacrylate, n-octadecyl acrylate, n-octadecyl methacrylate, 2-perfluorobutyl ethyl acrylate, 2,2,2-trifluoroethyl methacrylate, methyl 2,2,3,3-tetrafluoropropyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 1,1,1,3,3,3-hexafluoro methacrylate Isopropyl ester, 2,2,3,3,3-pentafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,4,4,4-hexamethacrylate Fluorobutyl and 2,2,3,3,4,4,4-Heptafluorobutyl methacrylate. The electrophoretic display of claim 15, wherein the macromonomer includes a terminal functional group selected from the group consisting of an acrylate group, a vinyl group, or a combination thereof. The electrophoretic display of claim 1, wherein the dispersion fluid is encapsulated in a microcapsule. The electrophoretic display as claimed in claim 1, wherein the dispersion fluid is encapsulated in the cells. The electrophoretic display of claim 1, wherein the dispersion fluid is encapsulated in a polymer matrix.